ERF for Frambozadrine in rats

Scope
Frambozadrine dose-response function in rats describes the long-term health impact(s) caused by frambozadrine as a function of dose in rats. This dose-response function applies only to continuous long-term exposures of frambozadrine (like in chronic studies).

Definition

Causality

Upstream variables not defined.

Data

Toxicological data about frambozadrine in rats.

Dose(mg/kg-day)	Total no rats	Hyperkeratosis
Male
0	47	2
1.2	45	6
15	44	4
82	47	24
Female
0	48	3
1.8	49	5
21	47	3
109	48	33

Plausible dose-response functions

• Generalized dose-response function
• Multistage model (first order)
• Multistage model (second order)
• Weibull model

Formula

Methods for estimating dose-responses

• Bootstrap method
• Probabilistic inversion
• Non-parametric Bayesian estimation
• Bayesian model averaging

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Unit

probability of impact

Result

It is not clear which of the plausible methods for estimating the result is the best. The discussion is ongoing. D↷

Non-parametric Bayesian estimation

Males and Females combined

Dose levels	MLE	Prior	Posterior mean	Variance
0	0.053	0.125	0.0571	0.0634
1.2	0.133	0.25	0.1052	0.0348
1.8	0.102	0.375	0.13	0.0241
15	0.091	0.5	0.154	0.021
21	0.064	0.625	0.1799	0.0551
82	0.511	0.75	0.4969	0.2762
109	0.687	0.875	0.687	0.2778